Socket contact c spring



Feb. 27,1968 J. w. MASTON SOCKET CONTACT C SPRING zsneets-sheet 1 FiledDec. 30. 1965 U wm mm ww rill:wllfiqillllllllllllfi SM \n m mm JbMes W Msra/v Feb. 2' 7 1968v J. w. MASTON SOCKET CONTACT C SPRING 2Sheets-Sheet 2 Filed Dec. so, 1965 United States Patent 3,371,3tl8SUCKET CUNTACT C SEEING James W. Masters, Altadena, Califl, assignor toInternational Telephone and Telegraph Corporation, New York, N.Y., acorporation of Maryland Filed Dec. 30, 1965, Ser. No. 517,641 4 Claims.(Cl. 339-256) ABSTRACT OF THE DISCLGSURE A tubular connector forreceiving a male connector therein has a pair of longitudinallyextending slits located at opposite sides of the connector and passingcompletely through the connector body. An elongated spring of generallyC-shape cross section fits over the tubular connector with itslongitudinal edges received within the slits, one of the edges extendinginto the tubular cavity for resiliently urging the male connector intocontact with the tube wall.

This invention relates to electrical connectors and in particular to animprovement in a connector wherein a socket contact element ischaracterized by a C spring which biases a contact pin inserted in thesocket against the wall of the socket.

Objects of the invention are to provide a connector socket featureing aspring resiliently protruding into the bore of the socket for thefunction indicated, and which is not damaged or rendered ineffective byan oversize probe or careless use thereof, the parts of which socket areeasy to manufacture and relatively inexpensive to as semble, whichaffords redundant electrical paths, and which, once assembled, remainsintact.

The invention in general comprises an electrical connector socket forreception of a pin contact terminal wherein the socket embodies a bore-dtubular member open at its forward end and having circumferentiallyseparated longitudinal slots through the wall of the tubular member, anda spring member generally C-shaped in cross section and conforminggenerally to the external surface of the tubular member embodying oneend projection or flange seating in one of the slots, this end flangehaving a radial dimension less than the thickness of the Wall of thetubular member so that it does not protrude into the bore of the same,and the spring is formed with a second end projection or flange whichseats in the other one of the slots, this second end flange having aradial dimension greater than the thickness of the wall of the tubularmember so that the second end flange protrudes into the bore of thetubular member, the spring being snapped into place and being retainedon the tubular member by engagement of the flanges in the respectiveslots, and the second flange being adapted resiliently to urge a pincontact member inserted in the tubular member toward the surface of thebore generally diametrically opposite the position of the second flange.

The foregoing objects and general features of the invention, and others,will more fully appear from the drawings and the description whichfollows.

In the drawings:

FIGURE 1 is a perspective view of the connector with the pin and socketseparated.

FIGURE 2 is a view of the connector with the pin and socket joined.

FIGURE 3 is an enlarged longitudinal section of the socket.

FIGURE 4 is a perspective view of the C spring employed in the socket ofthe previous figures.

FIGURE 5 is a magnified cross section of the socket taken on the line5-5 of FIGURE 1.

FIGURE 6 is a similar view taken on the line 66 of FIGURE 2 showing thepin inserted.

FIGURE 7 is a view of the same general character as FIGURE 5illustrating a C spring with a modification over the form of FIGURE 4.

FIGURE 8 is a perspective view of the C spring illustrated in FIGURE 7.

The connector 15 shown in FIGURES 1 and 2 comprises a socket 16 and apin 17 adapted to be inserted in the socket. The socket embodies atubular member or section 18 and a termination section 19, the latterbeing either hollow or solid depending upon the desired terminationthereof in conjunction with an electrical con-ductor not shown. Themeans of termination is not a part of the present invention nor is aninsulation block or member in which the socket may be mounted in anypart of the present invention. It is obvious to anyone skilled in theart that while the socket and pin can be employed individually formaking an electrical connection, in ordinary practice, especially inminiaturization, these respective parts are mounted in insulator membersusually in pluralarrangement for effecting a multiplicity of independentconnections in a small, compact arrangement.

The tubular member has a bore 2% open at the forward end 21 andextending rearwardly at least a sufiicient distance to receive the pin17. The outside diameter of the pin is sufficiently less than thediameter of the bore for easy insertion fo the pin inasmuch as no tightfriction fit between the two parts is required, other than that impartedby the C spring as later described.

Preferably, although it is not absolutely essential, the exterior of thetubular member is formed with an intermediate annular undercut 22providing shoulders 23 and 24 at each end.

Through the wall of the reduced section of the tubular member defined bythe undercut 22 are provided slots 25 and as which preferably aredisposed apart and which are elongated and extend parallel to the axisof the bore and are generally coextensive with the length of theundercut 22, although it is preferable that the slots extend beyond theshoulders 23 and 24 for a short distance. It is important, however, thatthe forward end 21 provides a circularly uninterrupted closed entry,which should be chamfered as shown at 27, and that an uninterruptedannular section at the rear end of the bore be incorporated, so that thetubular member does not spread when the pin is inserted.

A spring 3h is employed, this spring having the overall general form ofa semi-cylinder preferably elongated relative to its diameter and incross section generally resembling the letter C. The shape and size ofthe spring is such that in retraction it snugly conforms to the outersurface of the undercut 22 or if there be no undercut to the outersurface of the tubular member in the region of the slots 25 and 26, andthat its axial dimension be no greater than the length of the undercutportion if that be present. In such case, the shoulders 23 and 24restrict the spring against axial movement. Otherwise, such restrictionwould be provided by the ends of the slots. The spring embodies what maybe designated a non-working end 31 and a working end 32. These ends aredisposed diametrically opposite one another at a circumferentialseparation approximately 180 and they are illustrated as includingprojections or flanges 31a and 32a extending radially inwardly towardthe axis of the spring, eing angled in from the cylindrical plane of themain body 33 of the spring.

The radial dimensions of the flange 31a is less than the thickness ofthe tubular member at the section where insertion occurs, to bedescribed. The radial measurement of the flange 32a is greater than thethickness of the section of the tubular member where the flange 32a isinserted, so that when the spring is assembled on the tubular memberthis flange will protrude into the bore of the tubular member. Thespring may be formed whereby the flange 32a is made of a fold-back ofthe spring material to contribute a greater surface contact with the pinwhen inserted, and this flange also preferably is radiused or chamferedas at 33 to provide a lead-in.

The spring and tubular member are assembled by inserting the flange 31aof the non-Working end into one of the slots in the tubular member, andby exerting a radial pressure on the spring moving the flange 32a intoalignment with the opposite slot whereupon the spring will snap intoplace and will be permanently retained on the tubular member by thecooperation of the two flanges.

The spring may be made of any suitable spring material, various metalsbeing suitable for such purpose, and inasmuch as the spring does nothave to function as a conductor, certain plastic materials are alsousable.

When the spring and tubular member are assembled the socket is completeand ready for use. The pin 17 is inserted into the socket and encountersthe chamfered end 33 of the spring flange 32a, riding against thisflange as the insertion is completed. Thus, upon insertion, the springbearing upon the pin biases it resiliently against the diametricallyopposite wall of the bore. Inasmuch as the opposite wall of the bore isdivided to considerable extent by the slot in which the flange 31a ofthe spring reposes, redundant electrical paths are afforded whichcontribute to the efficiency of the electrical connection. The diametriclimitations of the bore 20 prevent the pin from pushing the flange 32aout of the slot in which it rides, and consequently the spring remainsin place irrespective of repeated insertions of the pin.

The fold-back illustrated for the working end 32 of the spring can beeliminated, and this working end can be a single thickness similar tothe non-working end 31 except that it extends through the wall of thetubular member. A rounded edge on the flange 3201, as illustrated, ispreferable to a flat sharp edge because it operates more smoothly andhas less tendency to scratch or abrade the pin. If desired the edge maybe liquid-honed or Teflon coated to reduce friction when the pin isinserted or withdrawn.

Another form of working end on the spring is shown in FIGURES 7 and 8.In this one the non-working end 31 is the same as in the form previouslydescribed. The working end 32, however, utilizes a projection or flangein the form of a dimple 50, preferably elongated as shown, which can bedrawn or stamped if the spring is made of sheet spring material, ormolded if plastic, and either left relatively open as illustrated inFIGURE 7 or the sidewalls pinched together after the general formationof the form first described as seen in FIGURE 5. Instead I of a singledimple it is obvious that a series of dimples in straight alignment (notillustrated) could be substituted.

Whichever form is employed, the spring cannot be damaged by use of anoversized probe or careless use of a probe when testing circuits,because if the probe is oversized, yet of sufliciently small diameter tobe inserted into the socket it will simply push the spring through theslot to the wall of the bore, and upon withdrawal of the probe thespring will return to its working position protruding into the bore.

While it is preferred that the slots be circumferentially spacedapproximately 180 both for optimum retention of the spring in itsassembly with the tubular member and also for a truly diametric pressureof the working end of the spring against the pin of the connector yetthere may be a workable variation in the respective locations of theslots and consequently in the shape and ends of the spring. Thethickness of the spring preferably is slightly less than the depth ofthe undercut 22 so that if the socket is mounted in a bore of theinsulation block which 4 tightly houses the ends of the tubular member,there will be room within the bore of the insulation block for theworking end of the spring to move outwardly under the influence of a pinbeing inserted. An alternative would be to provide a relief in the boreof the insulation block.

The connector has been described with the tubular element of the springand the contact portion of the pin all in circular cylindrical forrn.While this probably is the most common form in which the connector willbe embodied, the principles of the invention are applicable to a socketwith a square or other polygonal cross section in which case the crosssection of the spring would define a block letter C or a modificationconforming generally to the outside contour of the tubular member, andthe flanges of the spring would be angled from the main body of theletter C radially inwardly toward each other.

Although I have herein shown and described my invention in which I haveconceived to be the most practical and preferred embodiments, it isrecognized that departures may be made therefrom within the scope of myinvention, which is not to be limited to the details disclosed hereinbut is to be accorded the full scope of the claims so as to embrace anyand all equivalent devices.

What I claim as new and desire to secure by Letters Patent is:

1. An electrical connector comprising: a socket including a hollow tubehaving diametrically opposite first and second longitudinally extendingslots therethrough; a generally C-shaped spring surroundingapproximately onehalf of the external surface of said tube, said springhaving first and second ends bent towards each other to extend radiallyinto said slots, said first end being shorter than the thickness of saidtube from the bend at said first end so as not to project beyondinternal surface of said tube, said second end being longer than thethickness of said tube from the bend at said second end so as to projectbeyond internal surface of said tube, said second slot having side wallsparallel to a plane through the axis of said tube, said second springend having a width such that it substantially fills the space betweensaid second slot side walls wherein said second spring end is in slidingengagement with said second slot side walls, said side walls therebyfirmly guiding radial movement of said second spring end in said secondslot; and a pin slidable into said socket, said second spring end beingengageable with said pin for resiliently urging said pin into contactwith the internal surface of said tube.

2. The invention as defined in claim 1, wherein said second spring endhas parallel side walls for secure sliding engagement with said secondslot side walls.

3. The invention as defined in claim 1, wherein said tube has acylindrical internal surface and said pin has an uninterruptedcylindrical external surface of a diameter only slightly smaller thanthat of said tube internal surface.

4. The invention as defined in claim 3, wherein said second spring endhas parallel side Walls for secure sliding engagement with said secondslot side walls.

References Cited UNITED STATES PATENTS 3,123,119 3/1964 Maloof 15ll13,169,817 2/1965 McKee s 339-256 3,205,474 9/1965 Culver ct al. 339-256X FOREIGN PATENTS 232,573 2/1961 Australia.

20,458 1911 Great Britain.

OTHER REFERENCES German printed application 1,128,500, April 1962.

MARVIN A. CHAMPION, Prinmry Examiner.

P. TEITELBAUM, Assistant Examiner.

